Yes and Deutsche Bahn is planning on doing it for all tracks where this is commercially and technologically feasible. The remaining tracks will mostly be battery electric trains and hydrogen.
That was a bit terse: the reason this isn't a serious answer is because Germany is burning large amounts of coal to make electricity, because of the natural gas shortage.
Turning electricity into hydrogen at around an 80% loss by the time it hits the fuel cell doesn't even begin to pencil out.
Some people plan more than a few years ahead. These technologies are an attempt at electrifying activities which cannot be powered directly from the grid in a future where all electricity comes from sustainable sources.
An 80% loss is a perfectly reasonable thing to accept if that's what it takes to make your energy supply portable and you produce your hydrogen using cheap power generated during peak sunlight hours by solar panels that could not otherwise be stored.
Switch to renewables and storage for energy production, switch over everything to electric, making it more efficient. Then let the natural systems deal with the remaining excess carbon how they deal with volcanic co2.
It is up to one's empathy, but mercy isn't something strictly directed towards humans. For some people it is universal, others have no mercy even for fellow humans.
It's as "green" as the electricity used for the hydrogen production. The idea is to use hydrogen as energy storage, produced from surplus wind and solar energy.
